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12 Cards in this Set

proteins interacting with DNA that turn prokaryotic genes on or off are called what?

operons

Operons are turned on when what?

when lactose is present

Operons are turned off when what?

when lactose is absent

What does DNA packing do?

tightly coils DNA so that it can fit in the nucleus and controls access to DNA

What are histones and wat do they look like?

small proteins that attach to DNA, small pink circles (picture 3rd page)

what is a nucleosome?

a region of DNA that is wrapped around 8 histone proteins

what is the process of a nucleosome wrapping with a helix?

the nucleosomes are wrapped into a helix, and then the helix is supercoiled

what is x-chromosome inactivation? why does it occur?

one x chromosome in female mammals is inactivated, this happens so that the cell can handle 2 x chromosomes at once by inactivating one

what are the general steps in cloning a mammal?

1)remove the nucleus from an egg cell 2) grow egg into an early embryonic stage 3)implant the egg into surrogate mother

What is the difference between embryonic stem cells and adult stem cells?

embryonic stem cells can grow into any cell or tissue type needed under the right conditions, but raise ethical issues, Adult stem cells are more difficult and can only differentiate into a gew cell types, but do not raise the same type of ethical dilemma

what is embryonic stem cells and what is your opinion

stem cells derived from an early stage of an embryo. I feel that more research should be done to find out if any medical benfits can be derived from it and if this is the case, then research should continue to help more people